Varying Sintering Temperature Research Articles

Impact of Sintering Temperature Variation on Porous Structure of Mo2TiAlC2 Ceramics.

Mo, TiH2, Al and graphite elemental powders were used as starting materials for the activation reaction sintering process, which was employed to fabricate porous Mo2TiAlC2. The alteration of phase constitution, volume expansion, porosity, pore size and surface morphology of porous Mo2TiAlC2 with sintering temperatures ranging from 700 °C to 1500 °C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and pore size tester. Both the pore formation mechanism and activation reaction process at each temperature stage were investigated. The experimental results illustrate that the sintered discs of porous Mo2TiAlC2 exhibit obvious volume expansion and pore structure change during the sintering process. Before 1300 °C, the volume expansion rate and porosity increase with the increment of temperature. However, with the sintering temperature above 1300 °C, the volume expansion rate and porosity decrease. At the final sintering temperature of 1500 °C, porous Mo2TiAlC2 with a volume expansion rate of 35.74%, overall porosity of 47.1%, and uniform pore structure was synthesized. The pore-forming mechanism of porous Mo2TiAlC2 is discussed, and the evolution of pressed pores, the removal of molding agents, the decomposition of TiH2, and the Kirkendall effect caused by different diffusion rates of elements in the diffusion reaction are all accountable for the formation of pores.

Investigation of Dependence of Magnetic Properties on Sintering Temperature of Eu<sub>1.85</sub>Ce<sub>0.15</sub>CuO<sub>4+α-δ</sub> Prepared by Sol-Gel Method

Differences in particle size can affect the magnetic properties of superconductors. At the nanoscale, superconductors have different magnetic properties than those at the micro or submicron size. The difference in particle size in superconducting materials can be obtained by giving the sintering temperature difference. In this work, we focus only on the magnetic properties in Eu1.85Ce0.15CuO4+α-δ (ECCO) in the optimal-doped regime prepared by the sol-gel method with various sintering temperatures 700 °C, 800 °C and 900 ° C sizes with an annealing temperature 800 °C to obtain different particle. The lattice parameters and crystallite size were obtained using XRD. Based on the XRD results, the higher the sintering temperature variation, the larger the crystallite size produced with lattice distortion and expansion with a decrease in particle size. The magnetic properties of these materials have been investigated using a superconducting quantum interference device (SQUID) at temperatures between 2 K and 30 K with the applied field at 5 Oe. Based on the SQUID measurement, the magnetic properties of samples sintering at 700 °C and 800 °C were found to be ferromagnetic-like behaviour, while sintering at 900 °C was found to be paramagnetic with no trace of the superconductivity phase. The differences response of magnetic properties can be associated with the effect of the differences size of the crystallites in each material, that can relate to uncompensated spins produced by the surface effect.

Preparation of Nickel (Ni) doped SrTiO3 and effects of sintering temperatures on its properties as photocatalyst

SrTi0.97 Ni0.03O3 photocatalysts with varied sintering temperatures of 900°C and 1000°C have been successfully prepared via the co-precipitation method. This study aimed to determine the effect of temperature on SrTi0.97 Ni0.03O3 photocatalyst including the microstructure, atomic bonding, and photocatalyst activity. X-Ray Diffraction (XRD) data revealed an increase in the crystallite size with increasing the sintering temperature. Fourier Transform Infrared (FTIR) results confirmed the formation of Sr-Ti-O bonds followed by the presence of CH impurities that the impurities decreased at 1000°C. The photocatalyst activity was tested using methylene blue (MB) degradation in SrTi0.97 Ni0.03O3 photocatalysts under UV rays. The time for the irradiation process varied from 3, 4, to 5 hours. The degraded result was examined using a UV-Vis spectrophotometer to estimate the %degradation. The results demonstrated that the sintering temperatures do not considerably impact MB degradation. Further, the best treatment for SrTi0.97Ni0.03O3 to attain the highest MB degradation of 49.9% is at 900°C with 5 hours of irradiation.

Preparation of In Situ Growth Multiscale β-Sialon Grain-Reinforced Al2O3-Based Composite Ceramic Tool Materials

A kind of multiscale β-sialon grain-reinforced Al2O3 matrix composite ceramic tool material, named ASN, was prepared and studied. For the ASN, β-sialon (molecular formula: Si4Al2O2N6) was synthesized in situ by a hot-pressing and solid-solution reaction process. A total of six samples were prepared at varying sintering temperatures and holding times under vacuum conditions. The solid solution reaction mechanism of β-sialon, the phase composition, mechanical properties, microstructure, and strengthening and toughening mechanisms of the composite ASN were investigated. As a result, within the experimental parameters, an optimal ASN tool material was obtained under a pressure of 32 MPa and at a temperature of 1550 °C for 20 min. The tested mechanical properties of the optimal sample were as follows: flexural strength 997 ± 59 MPa, fracture toughness 6.4 ± 0.3 MPa·m1/2, Vickers hardness 18.2 ± 0.4 GPa, and relative density 98.1 ± 0.2%. According to crystal defect theory, the solid solution reaction mechanism of in-situ-synthesized β-sialon in an Al2O3 matrix involves a double mechanism of unequivalence (or hetero-valence) and interstitial filling. The multiscale β-sialon grains mainly consisted of four grains, which were elongated β-sialon grains with a diameter of 0.3-0.4 μm and an aspect ratio of 6-9, elongated β-sialon grains with a diameter of 70 nm and an aspect ratio of 10, β-sialon whiskers with a diameter of 0.2 μm and an aspect ratio of 12-15, and intragranular β-sialon whiskers with a diameter of 70 nm. The mechanical properties were improved due to strengthening and toughening mechanisms, such as mixed structure mode (intergranular and transgranular), elongated grain pullout, interface bonding, crack reflection, pinning, and bridging.

Effect of sintering temperature on re-distribution of cations, electronic structure and tuning of optical band gap and ferromagnetism in Mn0.1Co0.9Fe2O4 spinel ferrites

Abstract Manganese-ion doped cobalt ferrite with the composition Mn0.1Co0.9Fe2O4 was synthesized by the self-combustion method and sintered at 800 °C, 900 °C and 1000 °C, represented as MCF-800, MCF-900 and MCF-1000, respectively. X-ray methods observed a single-phase cubic spinel formation. XPS analysis revealed the distribution of Mn3+ and Mn2+ ions in the tetrahedral A and octahedral B sites. Optical absorption studies confirmed an energy bandgap of 1.2505 eV for the sample MCF-1000, corresponding to near IR absorption useful for catalytic and water-splitting applications. The VSM measurements revealed a maximum magnetization (Ms) of 79.612 emu/g for the sample MCF-1000. The maximum entropy method (MEM) electron density distribution studies revealed different strengths of electron density for the cation tetrahedral site A and octahedral site B depending on sintering temperature variation. The sample sintered at 1000 °C with the A–O covalent and B–O ionic bonds with mid-bond densities of 1.903 e/Å3 and 0.381 e/Å3 may be useful for ferromagnetic applications. The magnetic, optical, and electronic analyses confirm that the sample MCF-1000 may be best suited for low-cost catalytic, water splitting and ferrite applications.

Characteristics of Bauxite Residue–Limestone Pellets as Feedstock for Fe and Al2O3 Recovery

Experimental research was carried out to produce pellets from bauxite residue for the further extraction of iron and alumina. Bauxite residue and limestone with three different mixture compositions were pelletized experimentally via agglomeration followed by drying and sintering at elevated temperatures. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used for the phase and microstructural analysis, respectively. Tumble, abrasion, and breaking load tests were applied to determine the strength of the pellets. For measurement of porosity and surface area, mercury porosimetry and BET surface area methods were applied. It was found that at 1100 °C sintering temperature, all the three sintered pellet compositions have a moderate porosity and low strength, but the reverse result was found when 1200 °C sintering temperature was applied. Moreover, for the pellets sintered at 1150 °C high strength and proper porosities were obtained. In the sintered pellets, iron present in form of brownmillerite (Ca2Fe1.63Al0.36O5), srebrodolskite (Ca2Fe2O5), and fayalite (Fe2SiO4), while alumina present mostly in gehlenite (Ca2Al2SiO7) and little fraction in mayenite (Ca12Al14O33) and brownmillerite phases. The identified phases are the same for of the three pellets, however, with variations in their quantities. Porosity and mechanical properties of pellets are inversely related with both varying sintering temperature and composition. It was found that with more CaCO3 use in pelletizing, higher porosity is obtained. However, with increasing sintering temperature the strength of the pellets increases due to clustering of particles, while porosity decreases.

FTIR spectrum analysis to predict the crystalline and amorphous phases of hydroxyapatite: a comparison of vibrational motion to reflection.

Hydroxyapatites were synthesized from calcium carbonate and ortho-phosphoric acid in amorphous and crystalline phases by varying sintering temperature from 300 to 1100 °C maintaining an increment of 200 °C. The asymmetric and symmetric stretching, and bending vibrations of phosphate and hydroxyl groups were explored in Fourier transformation infrared (FTIR) spectra. Although the FTIR spectra revealed identical peaks in the full range (400-4000 cm-1 wavenumber), the narrow spectra exerted variations by splitting peaks and intensity. The intensities of peaks at 563, 599, 630, 962, 1026, and 1087 cm-1 wavenumbers were intensified gradually with the augmentation of sintering temperature, and the relation between the relative peak intensity and sintering temperature was correlated with the aid of the good linear regression coefficient. Peak separations were also found in the case of 962 and 1087 cm-1 wavenumbers when the sintering temperature was equal to or exceeded 700 °C. The conventional X-ray diffraction (XRD) technique was also employed to explore the crystalline and amorphous phases of synthesized hydroxyapatites.

Effect of Sintering Parameters on the Mechanical Properties and Wear Performance of Alumina Inserts

The sintering temperature and holding time have a significant impact on the densification of a ceramic compact. In this study, alumina inserts were made with varying sintering temperatures and holding times. The procedure began with the compacting of alumina powders inside a mould with trapezium and round shapes. These inserts were then sintered between 1200 °C and 1400 °C for 5 to 9 h holding time. The sintered samples underwent analysis based on the shrinkage size, density, and microstructure. The sample with the highest density was chosen for additional machining tests. The results showed that the alumina shrinkage ranged from 3 to 6%, with a maximum relative density of 91.3% recorded when the sintering parameter was applied at 1400 °C and a 9 h holding time. The transition of the grain growth was observed depending on the sintering temperature and heating duration. When machined with AISI 1045 carbon steel, the sintered alumina inserts achieved a maximum tool life of 35 s at a cutting speed of 350 m/min. The sintered inserts exhibited brittle characteristics with a dominant notch wear and abrasive mechanisms.

To Study the Effect of Varying Sintering Temperature and Reinforcement on Physical and Mechanical Characteristics of AA6061/SiC Composites

To Study the Effect of Varying Sintering Temperature and Reinforcement on Physical and Mechanical Characteristics of AA6061/SiC Composites

Microstructural characterization and properties of aluminium 7075/Mo prepared by microwave sintering for high-strength application

ABSTRACT Ceramic particulates are often used in reinforcement of aluminium alloys. The use of this particulates results in embrittlement and lowering of ductility. In tackling this, the present study involved the use of relatively ductile metal particles (molybdenum) as reinforcement. Molybdenum (Mo) powder was blended with Al-7075 powder at 4, 8 and 12 wt. %, compacted at 25 MPa, and microwave sintering was performed at 350, 450 and 550 °C. The effect of the variation in Mo dosage and sintering temperature on the phases, microstructure and properties was evaluated. The result showed varying phases and microstructural evolution in the composites. For all proportion of the Mo particles, 350 and 450 °C favoured porosity and sintered and relative densities, whereas 550 °C was detrimental to the properties. It was observed that 4 and 8 % Mo enhanced microhardness and tensile strength, while 12 % Mo showed a decrease in hardness and a strength. In the same way, sintering temperatures of 350 and 450 °C aided improvement in hardness and tensile strength, even as 550 °C exhibited lower property values. It was concluded that proportions of molybdenum not greater than 8 wt. % and sintering temperature not greater than 450 °C are suitable for property improvement.

Binder-jetting of TiCN-based cermets

ABSTRACT Additive Manufacturing is experiencing an upswing in many sectors of industry for a broad variety of materials. Processes are mainly developed for polymers and metals. For ceramics, hardmetals and especially cermets there are only a few additive processes suitable. The powder-based technique Binder-Jetting is one of these suitable processes with high productivity and relatively low green density. Within this study, TiCN-based cermets are printed by Binder-Jetting for the first time. The complexity of influences of the morphology and composition of cermet powders are discussed in regard to bulk density and material properties of printed and sintered parts. Studied TiCN-based cermet compositions represent different Ni and Mo2C contents. Main points of this investigation are further the adjustment of ratio of the raw materials for good sintering behaviour and their influence on the microstructures and as a function of varied sintering temperatures.

Properties of Perovskite Solar Cells with Low Temperature Sintered SnO2 Electron Transport Layers

This study investigated the photovoltaic properties and microstructure of perovskite solar cells (PSCs) with an ITO/SnO2/perovskite/HTL/Au electrode configuration, developed with varying sintering temperatures (100~200°C). The goal was to use SnO2 ink as the electron transport layer (ETL) by low-temperature sintering. TGA-DTA analysis was conducted to determine the optimum sintering temperature of the SnO2 ink and the photovoltaic properties were examined by solar simulator analysis. To analyze the microstructure, a 3D profiler, optical microscope, and scanning electron microscopy (SEM) were used. The TGA-DTA analysis results show that SnO2 ink was effectively sintered at the low temperature of 80°C and above. As for the photovoltaic(PV) properties, the PV efficiency was approximately 15% at 120~150°C, and increased to a maximum of 17.16% at 180°C, and then fell to 12% at 200°C. The RMS value, a representation of surface roughness, of the SnO2 layer according to sintering temperature incrementally decreased, reached its lowest at 180°C, before finally increasing. The microstructure analysis showed that the perovskite layer formed on the SnO2 at a sintering temperature of 180°C had a relatively greater grain size of 402 nm and a thickness of 432 nm, thereby improving the PSC’s PV properties. These results suggest it is possible to implement a PCS with SnO2 ETL by low temperature sintering process.

Synthesis of BaTiO<sub>3</sub> Ceramics Using Co-Precipitation and Solid-State Reaction Method with Sintering Temperature Variation

Barium Titanate (BT) is one of the most intriguing ferroelectric materials widely exploited both for academic and technological utilization. The study aimed to investigate characteristics of BT ceramics Synthesized by co-precipitation (BT-C) and solid-state methods (BT-S) with variation of sintering temperatures. Here, the sintering temperatures are 900°C, 1000°C, 1100°C, and 1200°C for 4 h of each The characteristics are microstructure, morphology, and dielectric properties evaluated using X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), and Inductance-Capacitance-Resistance (LCR) meter, respectively. As results, the XRD patterns shows a pure perovskite single phase of BT was obtained by solid-state method at sintering temperature of 1000°C. While, the same result was obtained by co-precipitation at sintering temperature of 1100°C. The average crystallite size of BT-C and BT-S ceramics are in close values and getting larger with the higher sintering temperatures. Meanwhile, tetragonality of the BT-C tends to be larger as compared to the BT-S. The morphology results revealed big formed particles agglomeration (>5 μm) of the BT-C ceramics and the densities proportionally increased as the higher temperatures exhibited less porosity of ceramics. Meanwhile, the BT-S grains were visible and agglomerated in a much smaller size with the density values were different as the change of the sintering temperatures. The dielectric permittivity of the BT-C and BT-S ceramics were increased with higher sintering temperature. Further, the BT-C ceramics possessed higher permittivity than the BT-S due to high densities (less porosity) of ceramics. The highest permittivity of 1150 at 40 kHz was achieved by BT-C at 1200°C.

Sintering Temperature Effects on Photocatalytic Activity of SrTi<sub>0.80</sub>Mn<sub>0.20</sub>O<sub>3</sub>

SStrontium titanate (STO) is well recognized as promising perovskite photocatalytic material. The catalytic characteristics of STO can be improved by modification with Mn metal. In this study, SrTi0.80Mn0.20O3 has been successfully fabricated using coprecipitation technique with varied sintering temperatures of 700°C, 800°C, 900°C, and 1000°C. This study aimed to investigate the effect of sintering temperature on the photocatalytic activity of SrTi0.80Mn0.20O3. The photocatalyst activity of SrTi0.80Mn0.20O3 could be observed by the degradation of Methylene blue (MB) dye. Based on the X-Ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) data, the SrTi0.80Mn0.20O3 has been made. The data also showed that the impurities phases have been reduced and eliminated by the higher sintering temperatures. Nevertheless, all varied samples of the SrTi0.80Mn0.20O3 have successfully exhibited their photocatalyst activity by degrading the MB dye under UV light irradiation with irradiation times of 0, 1, 2, 3, 4, 5, and 6 hours. According to the UV-Vis absorption data, the irradiation time could considerably decline the absorption peaks of MB dye in SrTi0.80Mn0.20O3. Besides, the higher sintering temperature did not influence the absorption peaks position but slightly changed their intensity (at the same irradiation time). Furthermore, the higher sintering temperature and longer irradiation time tended to produce higher DR% of up to 66.63%.

Synthesis and Characterizations of Novel Spinel Ferrites Nanocomposites Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4

In this study, novel spinel ferrites nanocomposites containing aluminum chromium zinc nanoferrites, Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4 have been fabricated and characterized to determine the properties of highly stable conduction materials. The nanocomposites have been synthesized through the sol–gel method. Zinc and aluminum-doped chromium ferrites were prepared with the stoichiometric composition ZnxAlx-0.5Cr0.5Fe2O4 with ammonium hydroxide solution (NH4OH) and polyethylene glycol (PEG) at different temperatures with consecutive steps. After sintering the final nanoferrites, characterizations for morphological, spectral properties, and crystallinity have been determined through scanning electron microscope (SEM), Fourier transformation infrared spectroscopy, and X-ray diffraction spectrometer, respectively. SEM micrographs presented that higher sample density and agglomeration of the nanocomposite outer surface with temperature increase. The investigation of the dielectric and conduction properties presented with varying sintering temperature and Al–Zn doping greatly influenced the dielectric properties of spinel nanoferrites dielectric properties: dielectric loss tangent and dielectric constant. The effects of various sintering temperatures provide synergistic effects on the morphology and dielectric conductivity features. The characterizations presented that the dopants (Al, Zn) enhanced the magnetic and electrical properties of both chromium nanoferrites which can be implemented in high frequency single-layered electromagnetic waves absorbing devices in electrical and medical appliances in future.

Morphological characteristics and electrical properties analysis of silica based on river and coastal iron sand

This study aims to analyze silica's morphological characteristics and electrical properties based on the river and coastal sand. Iron samples were taken from Sompang river sand, East Lombok and Coastal Sand from Gading, Mataram City. The silica was synthesized using the sol-gel method with a sintering temperature variation of 100 to 175 ℃. Morphological characteristics samples analysis was done using SEM-EDX. The electrical properties of iron sand included measuring the dielectric constant using the parallel plate method. Furthermore, the resistivity was measured using the two-point probe method. In the silica-based on river sand sample, the resistivity value was inversely proportional to the sintering temperature. In contrast, the resistivity value of silica based on the coastal sand sample was directly proportional to the sintering temperature. Silica-based on river sand has a resistivity of about 7.1'104 Wm at a sintering temperature of 100℃ and 3.5'104 Wm at a sintering temperature of 175℃. Silica-based on river sand has a resistivity of about 1.8'104 Wm at a sintering temperature of 100℃ and 7.1'104 Wm at 175℃. This research is a preliminary study on the electrical properties of natural sand-based silica to improve understanding of the physical properties of silica to be used in technological applications, such as sensors. Furthermore, the dielectric constant value in the river sand sample was directly proportional to the sintering temperature. However, the dielectric constant in the coastal sand sample was inversely proportional to the sintering temperature. Silica-based on river sand has a dielectric constant of about 1.02'102 at a sintering temperature of 100℃ and 1.18'102 at 175℃. Silica-based on coastal sand has a dielectric constant of about 1.97'102 at a sintering temperature of 100℃ and 1.15'102 at 175℃.

Efek suhu sintering dan komposisi bahan terhadap karakteristik mekanik komposit berbahan limbah aluminium dan kaca menggunakan metode metalurgi serbuk

The waste has been a big problem for human and environment and has become a hot issue until recently. One of the wastes that we often encounter is aluminum waste. Aluminum waste can indeed be re-melted, but the results of the smelting will produce even more dangerous waste, namely Toxic Hazardous Material) waste. In addition to aluminum waste, there is also a lot of waste that we encounter in our daily lives, namely glass waste. This study aims to maximize the potential of aluminum waste and glass waste by examining the effect of variations in sintering temperature and material composition on the hardness and compressive strength of the composite. This research is started by crushing the solid material into the mesh of 100, the next stage is mixing the powder and then print it with 7 tons pressure load. The last step is sintering the specimens at temperatures of 390oC, 490oC, and 590oC with 60 minutes holding time. The results show that the highest hardness value is 60 HRF and the highest compressive strength value is 235.59 MPa. Macrostructure observation shows that there is greater porosity in the specimen with lower mechanical properties. Variation of sintering temperature has a directly proportional effect on the hardness and compressive strength values. Variation in the composition of material gives an inversely proportional effect on the two tests of mechanical properties when viewed from the percent addition of glass powder.

Microstructure tailoring of tungsten oxide for enhanced properties by varying sintering temperatures

Tungsten oxide (WO3) pellets were prepared using a hydraulic press and then sintered at temperatures between 900 and 1200 °C for 2 h. The as-prepared as well as the sintered pellets confirmed the presence of a single phase of WO3, having a monoclinic structure with increase in grain size and the variation in the morphology. The sintered density reached up to 97% of the theoretical value. The optical parameters and the I-V characteristics were found to be greatly dependent on the sintering temperature. This work delineates a strategy towards developing tungsten oxide pellets with enhanced properties especially focused on sensing applications.

Effect of sintering temperature on mechanical and bioactivity properties of bioactive glass and cordierite composite

In this study, a composite of bioactive glass (BG) and cordierite (BG-cord) was proposed to increase the strength and bioactivity of BG. Both BG and cordierite were separately synthesized with the method of glass melting, then, they were used to fabricate BG-cord with a variation of sintering temperature (600 to 1000 °C). The highest diametral tensile strength (DTS=30.54 MPa) was shown by the BG-cord with sintering temperature at 925 ºC. Bioactivity tests were conducted by soaking in Hank’s balanced salt solution (HBSS) for 7, 14, and 21 days. Apatite formation was examined by using a scanning electron microscope. The results showed that the sample showed good bioactivity with regards to the formation of apatite on the samples, confirmed by the detection of carbonate (C-O) and phosphate (P-O) absorption peaks by Fourier transform infrared spectroscopy and crystalline peaks in the X-ray diffraction pattern.

Impacts of low sintering temperature on microstructure, atomic bonds, and dielectric constant of barium titanate (BaTiO3) prepared by co-precipitation technique

Barium Titanate (BaTiO3 or BT) is one of which the most attractive ferroelectric materials that have been widely studied. The fabrication process affects the properties of ferroelectric materials where increasing the sintering temperature is one of the ways to improve their performance. In this study, BT has been synthesized using the co-precipitation technique. The samples were sintered for 4 h with varying sintering temperatures of 700°C and 800°C. The purpose of this study was to investigate the effects of variation of sintering temperatures on the microstructure, dielectric constant, and chemical bonds of BT. The micro structure observed by the X-Ray Diffraction (XRD) showed that the crystal size of the sample at 800°C was larger than the sample at 700°C. Furthermore, the Fourier Transform Infrared (FTIR) analysis revealed that increasing the sintering temperature decreased the intensity of the impurities’ peaks of C-H and C=O atomic bonds in the BT structure. The impurity that appear is the carbonate phase which does not decompose during the formation of BT. Moreover, based on the Resistance Capacitance Inductance (RCL Meter) examination, increasing the sintering temperatures could enhance the dielectric constant of the BT samples from 65 to 162. Thus, it can be inferred, that the increase in the sintering temperature could improve the crystal structure and decrease the impurities phases of the BT materials so that further could enhance the dielectric constant.